This invention relates to a pressure gas engine having a rotor, a plurality of adjacent and arcuately arranged fixed nozzles exhausting into adjacent arcuately arranged impulse buckets located in the rotor with each bucket having a curved impulse surface across which the high velocity gas sweeps in imparting rotational energy to the rotor.
Another feature of the invention is to provide a pressure gas engine in which the supply of gas to the engine is controlled by a movable valve, a portion of the pressurized gas is bypassed as bleed gas around the valve seat to the rear of the valve to provide valve closing back pressure thereon, a bleed passage from this back pressure side of the valve to increase or decrease the valve closing back pressure and centrifugally responsive means for opening and closing this bleed passage as a function of the speed of rotation of the rotor to control the position of the valve and thus the supply of pressure gas to the engine.